What they're looking for is, "Down sun, up moon." so the answer is to the west.
Sunlight on hazy air causes flare and scattering of light looking towards the sun so vis is usually better down-sun whare the air/haze is backlit.
Moonlight works the other way around, probably helped by the lower light levels giving better contrast towards the moon rather than away from it.
This is usually only significant when the light source is fairly low in the sky.
I thought every PPL was taught this?
Last edited by meleagertoo; 18th Oct 2018 at 10:48.